1. Field of the Invention
This invention relates to magnetic recording mediums such as magnetic audio or video tapes, magnetic disks including floppy disks and hard disks, and the like.
2. Description of the Prior Art
Magnetic recording mediums are run in frictional contact with a magnetic head and thus, they are required to have a magnetic recording layer having high durability.
In order to enable one to make a durable recording layer, it is the ordinary practice to form a magnetic recording layer in which a binder has been thermally cured. For instance, a polyfunctional isocyanate compound is added, in a solvent, to a binder resin such as a vinyl chloride-vinyl acetate-vinyl alcohol copolymer, a polyurethane resin or nitro cellulose, along with a magnetic powder, thereby obtaining a magnetic paint. This paint is applied onto a non-magnetic support and thermally cured to form a magnetic coating layer with an improved film strength.
However, the thermal curing treatment is apt to involve disadvantages such as blocking and curling problems. With the thermosetting resin binders used above, the disadvantages involved by the curing are difficult to overcome. In order to avoid the curling problem, an additional annealing step is undesirably necessary.